Method of fabricating slide fasteners



Nov. 3, 1964 TOSHIAKI TAKAGI 3,154,343

METHOD OF FABRICATING SLIDE FASTENERS Filed Jan. 8, 1962 United States Patent 0 3,154,843 lrETHBD 0F FABREQ G SLEE FAfiTENERS Toshialri Talragi, Minami-hu, Osaka-SM, Ziapan, assignor to Nippon Shinpu Kabnshihi Keisha, Tolsyo-to, Japan, a joint-steel; company of Japan Filed .lan. $5, 1962, Ser. N 164,357 Qlairns priority, application Japan, Jan. 12, 1961, 36/?43 3 Claims. (Cl. 29-419) This invention relates to slide fasteners of the type commonly called zipper fasteners, and more particularly, it relates to a new method of fabricating slide fasteners of highly desirable characteristics.

it is an object of the present invention to provide a new method of fabrication whereby a special twisting turn is imparted to a starting material in the form of a flat strip to produce in a simple manner readily adaptable to mass production, a slide fastener member which has regularly spaced engagement parts.

It is another object of the invention to produce a new slide fastener utilizing the above-stated fastener member which, in the closed state, cannot be opened unintentionally by tensile force in the transverse direction or by bending and folding through 36% degrees of angle and pulling, yet can be opened by smooth disengagement by means of a slider.

it is a further object to provide a new slide fastener as above-stated which, in the closed state, provides a flexible joint between two articles which, on one side thereof, presents no protruding or raised ridgelike portion.

The foregoing objects, other objects, and advantages have been achieved by the present invention, which, briefly summarized in general terms, comprises the following procedure. The forming of the fastener member consists of two forming operation stages. The first forming stage comprises wrapping a strip of starting material of fiat, rectangular cross section in a helical path about a circular rod or mandrel and, then stretching this wrapped starting material in the axial direction. The second stage comprises winding the material obtained by the first stage about a bar or mandrel of slightly greater thickness than that of the rod used in the first stage in a helical path, the direction of which is opposite that of the helical path of the first stage. The material produced by this second stage is used as one slide fastener member of a pair of slide fastener members to constitute the complete fastener assembly. The other slide fastener member of the pair is similarly made except hat the helical directions in each of its forming stages are the opposite of the corresponding directions of the first slide fastener member. Each of the slide fastener members is fixed along a side edge thereof perpendicular to its engagement part to the side edge of one of the base articles to be fastened.

The nature and details of the invention will be more clearly apparent by reference to the following description of one representative embodiment when taken in conjunction with the accompanying drawings in which like parts are designated by like reference characters, and in which:

FIG. 1 is a perspective view showing a portion of a strip of starting material for the fabrication method of the present invention;

FlG. 2 is a partial side elevational view indicating the first forming stage according to the method of the present invention;

FIG. 3 is a partial side elevational view showing the intermediate material produced by the first forming stage;

FIG. 4 is a partial side elevational view illustrating the second forming stage;

FIG. 5 is a side elevational view showing the attachment of a slide fastener member to the edge of a base article;

FIG. 6 is a plan view showing a pair of slide fastener members in their engaged or closed state; and

FIG. 7 is an end elevational view, partly in cross section and with parts cut away, showing the completed slide fastener in the closed state.

Referring to the illustrations, beginning with FIG. 1, a strip of starting material 1 having a flat, rectangular cross section is prepared from a tough material which can be deformed elastically, such as for example, a light metal or a nylon material. This starting material 1 is first wrapped about a rod or mandrel 2 of circular cross section in a helical path of either a right-hand screw or a lefthand screw as indicated in FIG. 2. Then the said starting material is stretched in the axial direction to provide a first-stage formed material 3 which is twist turned along its entire length as shown in FIG. 3.

This first-stage formed material 3 is wound about a rod or mandrel 5 of slightly greater thickness than the rod 2 in a helical path the direction or" which is opposite that of the helical path of the first forming stage. During this step, crease-bent portions 6 are formed by the periphery of the rod 5, and a second-stage formed material as shown in FIG. 4 is obtained. The bending of the crease-bent portions 6 caused by the periphery of the rod 5 is limited to only those portions of the twist-turned strip material wound about the rod 5 which are substantially parallel to the peripheral surface of the rod 5'. Since a similar bending of the portions B or" the strip material which are substantially perpendicular to the rod 5 is diliicult or impossile, the crease-bent portions 6 are automatically formed at accurately constant geometrical intervals.

The material (FIG. 4) formed in the above-described manner is pulled from th rod 5 and is used as one of a pair of slide fastener members. This slide fastener memher 8 is fixed integrally to its supporting base material, for example, a flexible bead material 12 joined to one side edge ll of a tape it by the interweaving of a thread 23 which binds the twist-turned portion 9 of the side surface at 96 degrees of angle to the engaging portion of the slide fastener member 8 and a thread 14 which is connected to the bead material 12.

The slide fastener member 8 is combined with another similar member 8a to form a pair, the two members 8 and 8:: having mutually opposite directions of helical winding produced during their respective aforesaid second f rming stages. That is, if one member 3 is wound in a right-hand helical path, the other member 3a is wound in a left-hand helical path. Accordingly, the starting materials for the two members 3 and 8a are also wrapped in helical paths of mutually opposite directions d their respective first forming stages.

The mechanism of fastening, that is, the mutual engage ment or meshing of a pair of slide fastener members 8 and 5a will now be considered in detail. In the case of the embodiment illustrated in FIG. 7, since the rod 5 used a forming mandrel in the second forming stage is a bar with a square cross section, the helically wound fastener members 8 and 8:: have cross sections based on a square. In this embodiment, side edges 11 and 11a of a pair of tapes it? and Ella are crease-bent and joined to head materials 12 and 12a, respectively. The members 8 and 8a are so positioned on and so bound to the bead materials 12 and 12:: that, in the assembled state for operation, their respective twist-turned portions 15' and 15a, which are continuations of the helically wound members 8 and 8a from the attachment, twist-turned portions 9 and 9a by way of the crease-bent portions 6 and 6a, are caused to become mutually engaged or meshed.

For this purpose, it is necessary that the slider (not shown) for effecting this engagement of the members 8 and 8a have an internal guide slot which, unlike the horizontal slot of the conventional slider, imparts a rotation to the '3 members 8 and 8a so that, as the member 8 is rotated through 90 degrees of angle, the portions 15 and 15a are caused to be mutually inserted into the gaps in the opposite helical members. When the members 8 and 8a are fastened in the above manner, the bead materials 12 and 12a are caused .to be aligned tightly in parallel rows as shown in FIG. 7, the pair of fastener members 8 and 8a being fastened with their twist-turned portions 15 and 15 in'continuous engagement on one side of the said rows.

Since the mutually engaged helical members have mutually opposite helical directions, the orientations of the twist-turned portions 15 and 15a are also mutually opposite. Accordingly, once these portions are engaged, they offer extremely strong resistance to tensile force in the lateral direction. That is, the higher the lateral tensile force is, the greater is the tendency of the twist-turned portions 15 and 15a to enter into a state of tighter mutual engagement, wherefore unintentional disengagement is resisted automatically. For intentional disengagement, reverse rotation is imparted by means of the slider, whereby the twist-turned portions 15 and 15a are easily disconnected.

It will be apparent that the nature of the present invention differs from that of the conventional slide fastener wherein the engagement members are brought together in a planar manner, and protruding teeth mutually engage, or that of simple helical coils caused to engage each other. By the practice of the present invention, a strip starting material 1 is first formed into a helically wrapped configuration, then stretched in the axial direction to form a material 3 which has a twist-turned configuration along its entire length; then this material 3 is wound, in the opposite helical direction, about a rod 5 which is provided with guidecorners 4 to form crease-bent portions 6. The resulting fastener member consists of a continuous, twisted strip surface; and, at the same time, the crease-bent portions 6 precisely establish its cylindrical outer configuration suitable for its purpose as a fastener membe Moreover, since these crease-bent portions 6 are formed at only those portions of the twist-turned strip material which are substantial parallel to the peripheral surface of the rod 5, and the portions which are substantially perpendicular to the said surface and the contiguously adjacent portions are not crease-bent, uniform spacing or pitch of the crease-bent portions 6 is automatically established. Accordingly, by the use of simple helical winding steps, a continuous member with engagement gaps necessary for its purpose as a fastener member 8 is formed in a simple manner.

The engagement action of a pair of such slide fastener members, while being as smooth as that of the conventional helical types, is, moreover, extremely positive since the several twist-turned portions and 15a are mutually engaged.

Thus, by the practice of the present invention, aislide fastener which is superior to conventional slide fasteners in several features, particularly in resistance to unintentional disengagement, can be obtained by an extremely simple fabrication method, which, because of its simplicity and low cost is readily applicable to quantity prodnction.

It is a further advantage of the present invention that, by disposing the bead material 12 and 12a on and substantially flush with the outer or exposed surface of the article to be fastened, the fastener members 8 and 8a are totally hidden in the closed state, and a non-protruding, inconspicuous seam is obtained.

Although this invention has been described with respect to a particular embodiment thereof, it is not to be so limited as changes and modifications may be made therein which are within the full intended scope of the invention, as defined by the appended claims.

What is claimed is:

1. A method of manufacturing slide fasteners comprising winding a first strip of fiat rectangular material about a first mandrel of circular cross section in a helical path, removing said wound strip from said first mandrel, stretching said helically wound strip in an axial direction for obtaining a first twisted strip, winding said first twisted strip about a second mandrel of rectangular cross-section in a helical path in a direction opposite to the path about the first mandrel for forming a first spiral fastener component having crease bent portions provided by the corners of said second mandrel, removing said first component from said second mandrel, winding a second strip of flat rectangular material about a mandrel identical to said first mandrel in a helical path opposite to that of the first strip, removing said second helically wound strip from said mandrel, stretching said second helically wound strip in an axial direction, for obtaining a second twisted strip and winding said second stretched helically wound strip about a mandrel identical to said second mandrel in a helical path opposite to that of the first strip about'said second mandrelfor forming a second spiral fastener component having crease bent portions provided by the mandrel of rectangular cross-section, removing said second component from said mandrel, securing the first spiral fastener component to one side edge of a base article to be fastened, and securing the second spiral fastener component to the other side edge of the base article with said components being made engageable and disengageable by the manipulation of a slider cooperably associated therewith.

2. The method of manufacturing slide fasteners as claimed in claim 1, wherein said first and second strips are formed from tough material which can be subjected to a high degree of elastic deformation and which is highly resistant to fatigue due to repeated stress.

3. A method of manufacturing slide fasteners comprising winding a first strip of flat rectangular material about a first mandrel of circular cross-section in a helical path, removing said wound strip from said first mandrel, stretching said helically wound strip in an axial direction for obtaining a first twisted strip, winding said first twisted strip about a second mandrel of rectangular cross-section in a helical path in a direction opposite to the path about the first mandrel for forming a first spiral fastener component having crease bent portions provided by the corners of said second mandrel, removing said component from said second mandrel winding a second strip of fiat rectangular material about 'a mandrel identical to said first mandrel in a helical path opposite to that of the first strip, removing said second helically wound strip from said mandrel stretching said second helically wound strip in an axial direction for obtaining a second twisted strip, winding said second twisted strip about a mandrel identical to said second mandrel in a helical path opposite to that of the first strip for forming a second spiral fastener component having crease bent portions provided by said mandrel, removing said second component from said mandrel attaching said first fastener component to a fiexible elongated bead of substantially circular cross-section, attaching said second fastener component to a flexible elongated head of substantially circular cross-section, and securing said beads to supporting bases whereby the sides of said first and second spiral fastener components are engageable and disengageable by the manipulation of a slider operably associated therewith.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain June 8, 1943 

1. A METHOD OF MANUFACTURING SLIDE FASTENERS COMPRISING WINDING A FIRST STRIP OF FLAT RECTANGULAR MATERIAL ABOUT A FIRST MANDREL OF CIRCULAR CROSS-SECTION IN A HELICAL PATH, REMOVING SAID WOUND STRIP FROM SAID FIRST MANDREL, STRETCHING SAID HELICALLY WOUND STRIP IN AN AXIAL DIRECTION FOR OBTAINING A FIRST TWISTED STRIP, WINDING SAID FIRST TWISTED STRIP ABOUT A SECOND MANDREL OF RECTANGULAR CROSS-SECTION IN A HELICAL PATH IN A DIRECTION OPPOSITE TO THE PATH ABOUT THE FIRST MANDREL FOR FORMING A FIRST SPIRAL FASTENER COMPONENT HAVING CREASE BENT PORTIONS PROVIDED BY THE CORNERS OF SAID SECOND MANDREL, REMOVING SAID FIRST COMPONENT FROM SAID SECOND MANDREL, WINDING A SECOND STRIP OF FLAT RECTANGULAR MATERIAL ABOUT A MANDREL IDENTICAL TO SAID FIRST MANDREL IN A HELICAL PATH OPPOSITE TO THAT OF THE FIRST STRIP, REMOVING SAID SECOND HELICALLY WOUND STRIP FROM SAID MANDREL, STRETCHING SAID SECOND HELICALLY WOUND STRIP IN AN AXIAL DIRECTION, FOR OBTAINING A SECOND TWISTED STRIP AND WINDING SAID SECOND STRETCHED HELICALLY WOUND STRIP ABOUT A MANDREL IDENTICAL TO SAID SECOND MANDREL IN A HELICAL PATH OPPOSITE TO THAT OF THE FIRST STRIP ABOUT SAID SECOND MANDREL FOR FORMING A SECOND SPIRAL FASTENER COMPONENT HAVING CREASE BENT PORTIONS PROVIDED BY THE MANDREL OF RECTANGULAR CROSS-SECTION, REMOVING SAID SECOND COMPONENT FROM SAID MANDREL, SECURING THE FIRST SPIRAL FASTENER COMPONENT TO ONE SIDE EDGE OF A BASE ARTICLE TO BE FASTENED, AND SECURING THE SECOND SPIRAL FASTENER COMPONENT TO THE OTHER SIDE EDGE OF THE BASE ARTICLE WITH SAID COMPONENTS BEING MADE ENGAGEABLE AND DISENGAGEABLE BY THE MANIPULATION OF A SLIDER COOPERABLY ASSOCIATED THEREWITH. 